Facsimile recorders based on the electrooptical principle, henceforth called "optical printers", have been used for a long time. Published German Patent No. 32 14 584 discloses an optical printer in which the image information is outputted line by line. Electrodes are so deposited on a lead lanthanum zirconate titanate (PLZT) substrate that two lines of electrically controllable light gates are obtained. On each side of an areal main electrode extending in the line direction, a row of likewise areal finger electrodes is disposed. The light gates are formed in those areas of the substrate which are bounded by the ends of the finger electrodes and the long side of the main electrode. The light gates of one line are displaced by one light-gate width relative to those of the other, whereby the two lines are electricalls isolated one from the other. By a skilful arrangement of the electrodes, each line can be represented with the aid of 2N spots if there are N light gates per partial line. In many cases, however, such a resolution is not sufficient and higher resolution is desirable, particularly if the optical printer is to be used for reproducing colored subject copies.